An austenite NiTi shape memory alloy is processed by laser shock peening (LSP), and the mechanical properties is investigated. It is found that the thickness of shock affected layer is about 300 μm. The surface hardness of the specimen is increased by approximately 10% after LSP. The strain of the specimen is extracted from the images recorded in the tension by the digital image correlation technique in order to obtain the stress-strain curves. The superelastic stress-strain curves of the fully LSP processed NiTi material show no change in phase transition stress, the martensite yield stress decreases to about 100 MPa, and a loss of maximum transition strain about 13% after LSP. The ultrahigh-strain-rate plastic deformation by LSP results in dense dislocation underneath the surface which is responsible for the hardness increase and superelastic strain loss.